/*
 * Copyright (C) 2004, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
 * Copyright (C) 2006 Alexey Proskuryakov <ap@nypop.com>
 * Copyright (C) 2007-2009 Torch Mobile, Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "wtf/text/TextEncoding.h"

#include "wtf/OwnPtr.h"
#include "wtf/StdLibExtras.h"
#include "wtf/Threading.h"
#include "wtf/text/CString.h"
#include "wtf/text/TextEncodingRegistry.h"
#include "wtf/text/WTFString.h"

namespace WTF {

static const TextEncoding& UTF7Encoding()
{
    DEFINE_THREAD_SAFE_STATIC_LOCAL(const TextEncoding, globalUTF7Encoding, new TextEncoding("UTF-7"));
    return globalUTF7Encoding;
}

TextEncoding::TextEncoding(const char* name)
    : m_name(atomicCanonicalTextEncodingName(name))
{
    // Aliases are valid, but not "replacement" itself.
    if (m_name && isReplacementEncoding(name))
        m_name = 0;
}

TextEncoding::TextEncoding(const String& name)
    : m_name(atomicCanonicalTextEncodingName(name))
{
    // Aliases are valid, but not "replacement" itself.
    if (m_name && isReplacementEncoding(name))
        m_name = 0;
}

String TextEncoding::decode(const char* data, size_t length, bool stopOnError, bool& sawError) const
{
    if (!m_name)
        return String();

    return newTextCodec(*this)->decode(data, length, DataEOF, stopOnError, sawError);
}

CString TextEncoding::encode(const String& string, UnencodableHandling handling) const
{
    if (!m_name)
        return CString();

    if (string.isEmpty())
        return "";

    OwnPtr<TextCodec> textCodec = newTextCodec(*this);
    CString encodedString;
    if (string.is8Bit())
        encodedString = textCodec->encode(string.characters8(), string.length(), handling);
    else
        encodedString = textCodec->encode(string.characters16(), string.length(), handling);
    return encodedString;
}

bool TextEncoding::usesVisualOrdering() const
{
    if (noExtendedTextEncodingNameUsed())
        return false;

    static const char* const a = atomicCanonicalTextEncodingName("ISO-8859-8");
    return m_name == a;
}

bool TextEncoding::isNonByteBasedEncoding() const
{
    if (noExtendedTextEncodingNameUsed()) {
        return *this == UTF16LittleEndianEncoding()
            || *this == UTF16BigEndianEncoding();
    }

    return *this == UTF16LittleEndianEncoding()
        || *this == UTF16BigEndianEncoding()
        || *this == UTF32BigEndianEncoding()
        || *this == UTF32LittleEndianEncoding();
}

bool TextEncoding::isUTF7Encoding() const
{
    if (noExtendedTextEncodingNameUsed())
        return false;

    return *this == UTF7Encoding();
}

const TextEncoding& TextEncoding::closestByteBasedEquivalent() const
{
    if (isNonByteBasedEncoding())
        return UTF8Encoding();
    return *this;
}

// HTML5 specifies that UTF-8 be used in form submission when a form is
// is a part of a document in UTF-16 probably because UTF-16 is not a
// byte-based encoding and can contain 0x00. By extension, the same
// should be done for UTF-32. In case of UTF-7, it is a byte-based encoding,
// but it's fraught with problems and we'd rather steer clear of it.
const TextEncoding& TextEncoding::encodingForFormSubmission() const
{
    if (isNonByteBasedEncoding() || isUTF7Encoding())
        return UTF8Encoding();
    return *this;
}

const TextEncoding& ASCIIEncoding()
{
    DEFINE_THREAD_SAFE_STATIC_LOCAL(const TextEncoding, globalASCIIEncoding, new TextEncoding("ASCII"));
    return globalASCIIEncoding;
}

const TextEncoding& Latin1Encoding()
{
    DEFINE_THREAD_SAFE_STATIC_LOCAL(const TextEncoding, globalLatin1Encoding, new TextEncoding("latin1"));
    return globalLatin1Encoding;
}

const TextEncoding& UTF16BigEndianEncoding()
{
    DEFINE_THREAD_SAFE_STATIC_LOCAL(const TextEncoding, globalUTF16BigEndianEncoding, new TextEncoding("UTF-16BE"));
    return globalUTF16BigEndianEncoding;
}

const TextEncoding& UTF16LittleEndianEncoding()
{
    DEFINE_THREAD_SAFE_STATIC_LOCAL(const TextEncoding, globalUTF16LittleEndianEncoding, new TextEncoding("UTF-16LE"));
    return globalUTF16LittleEndianEncoding;
}

const TextEncoding& UTF32BigEndianEncoding()
{
    DEFINE_THREAD_SAFE_STATIC_LOCAL(const TextEncoding, globalUTF32BigEndianEncoding, new TextEncoding("UTF-32BE"));
    return globalUTF32BigEndianEncoding;
}

const TextEncoding& UTF32LittleEndianEncoding()
{
    DEFINE_THREAD_SAFE_STATIC_LOCAL(const TextEncoding, globalUTF32LittleEndianEncoding, new TextEncoding("UTF-32LE"));
    return globalUTF32LittleEndianEncoding;
}

const TextEncoding& UTF8Encoding()
{
    DEFINE_THREAD_SAFE_STATIC_LOCAL(const TextEncoding, globalUTF8Encoding, new TextEncoding("UTF-8"));
    ASSERT(globalUTF8Encoding.isValid());
    return globalUTF8Encoding;
}

const TextEncoding& WindowsLatin1Encoding()
{
    DEFINE_THREAD_SAFE_STATIC_LOCAL(const TextEncoding, globalWindowsLatin1Encoding, new TextEncoding("WinLatin1"));
    return globalWindowsLatin1Encoding;
}

} // namespace WTF
